Image sensors

ABSTRACT

Image sensors are provided. The image sensors may include a substrate including first, second, third and fourth regions, a first photoelectric conversion element in the first region, a second photoelectric conversion element in the second region, a third photoelectric conversion element in the third region, a fourth photoelectric conversion element in the fourth region, a first microlens at least partially overlapping both the first and second photoelectric conversion elements, and a second microlens at least partially overlapping both the third and fourth photoelectric conversion elements. The image sensors may also include a floating diffusion region and first, second and third pixel transistors configured to perform different functions from each other. Each of the first, second and third pixel transistors may be disposed in at least one of first, second, third and fourth pixel regions. The first pixel transistor may include multiple first pixel transistors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. Application No.18/155,785, filed Jan. 18, 2023, which is a continuation of U.S. Pat.Application No. 17/399,282, filed Aug. 11, 2021, which is a continuationof U.S. Pat. Application No. 16/711,987, filed Dec. 12, 2019, which is acontinuation of U.S. Pat. Application No. 15/862,013, filed Jan. 4,2018, which claims priority under 35 U.S.C. §119 to Korean PatentApplication No. 10-2017-0045155 filed on Apr. 7, 2017 in the KoreanIntellectual Property Office, the disclosures of which are herebyincorporated by reference in their entireties.

BACKGROUND

The present inventive concept generally relates to the field ofelectronics and, more particularly, an image sensor.

An image sensor is a sensor that converts an optical image into anelectric signal. Recently, with the development of the computer industryand the communication industry, there has been an increasing demand foran image sensor with improved performance in various fields such as adigital camera, a camcorder, a personal communication system (PCS), agame device, a security camera and a medical micro camera.

The image sensor may be classified into, for example, a charge coupleddevice (CCD) image sensor and a CMOS image sensor. In the CMOS imagesensor, a simple driving scheme may be used, and signal processingcircuits may be integrated into a single chip, thereby realizingminiaturization of a product. Also, the CMOS image sensor may have verylow power consumption, and thus, may be easily applied to a product withlimited battery capacity. In addition, the manufacturing cost may bereduced by using compatible CMOS process technology. Therefore, the CMOSimage sensor is rapidly increasing in use as high resolution may berealized along with technology development.

As semiconductor devices have become highly integrated, image sensorshave also become highly integrated. Accordingly, a sharing structurethat may include a plurality of pixels constituting one unit pixel andone unit pixel sharing pixel transistors may be beneficial.

SUMMARY

Aspects of the present inventive concept may provide an image sensorcapable of increasing the integration density by providing various pixelsharing structures.

Aspects of the present inventive concept also may provide an imagesensor capable of improving the performance of the image sensor byproviding plural transistors for at least one pixel transistor.

However, aspects of the present inventive concept are not restricted tothe one set forth herein. The above and other aspects of the presentinventive concept will become more apparent to one of ordinary skill inthe art to which the present inventive concept belongs by referencingthe detailed description provided below.

According to some embodiments of the present inventive concept, imagesensors are provided. The image sensors may include a substrateincluding a first region, a second region disposed adjacent to the firstregion in a first direction, a third region disposed adjacent to thefirst region in a second direction that intersects the first direction,and a fourth region disposed adjacent to the second region in the seconddirection and disposed adjacent to the third region in the firstdirection, a first microlens disposed to overlap the first and secondregions in a plan view, a first photoelectric conversion elementdisposed in a first pixel region of the first region and a secondphotoelectric conversion element disposed in a second pixel region ofthe second region. The first microlens may at least partially overlapboth the first photoelectric conversion element and the secondphotoelectric conversion element in the plan view. The image sensors mayalso include a second microlens disposed to overlap the third and fourthregions in the plan view, a third photoelectric conversion elementdisposed in a third pixel region of the third region and a fourthphotoelectric conversion element disposed in a fourth pixel region ofthe fourth region. The second microlens may at least partially overlapboth the third photoelectric conversion element and the fourthphotoelectric conversion element in the plan view. The image sensors mayfurther include first, second, third and fourth transfer gatesconfigured to control transfer of first, second, third and fourthsignals provided by the first, second, third and fourth photoelectricconversion elements, respectively, a floating diffusion regionconfigured to receive any one of the first, second, third and fourthsignals and first, second and third pixel transistors configured toperform different functions from each other. Each of the first, secondand third pixel transistors may be disposed in at least one of first,second, third and fourth pixel regions, the first, second, third andfourth pixel regions may be disposed in the first, second, third andfourth regions, respectively, and the first, second, third and fourthpixel regions may be different from the first, second, third and fourthpixel regions, respectively. The first pixel transistor may include aplurality of first pixel transistors

According to some embodiments of the present inventive concept, imagesensors are provided. The image sensors may include a substrateincluding a first region, a second region disposed adjacent to the firstregion in a first direction, a third region disposed adjacent to thesecond region in the first direction, and a fourth region disposedadjacent to the third region in the first direction, a first microlensdisposed to overlap the first and second regions in a plan view, a firstphotoelectric conversion element disposed in a first pixel region of thefirst region and a second photoelectric conversion element disposed in asecond pixel region of the second region. The first microlens may atleast partially overlap both the first photoelectric conversion elementand the second photoelectric conversion element in the plan view. Theimage sensors may also include a second microlens disposed to overlapthe third and fourth regions in the plan view, a third photoelectricconversion element disposed in a third pixel region of the third regionand a fourth photoelectric conversion element disposed in a fourth pixelregion of the fourth region. The second microlens may at least partiallyoverlap both the third photoelectric conversion element and the fourthphotoelectric conversion element in the plan view. The image sensors mayfurther include first, second, third and fourth transfer gatesconfigured to control transfer of first, second, third and fourthsignals provided by the first, second, third and fourth photoelectricconversion elements, respectively, a floating diffusion regionconfigured to receive any one of the first to fourth signals, and first,second and third pixel transistors configured to perform differentfunctions from each other. Each of the first, second and third pixeltransistors may be disposed in least one of first, second, third andfourth pixel regions, the first, second, third and fourth pixel regionsmay be disposed in the first, second, third and fourth regions,respectively, and the first, second, third and fourth pixel regions maybe different from the first, second, third and fourth pixel regions,respectively. The first pixel transistor may include a plurality offirst pixel transistors.

According to some embodiments of the present inventive concept, imagesensors are provided. The image sensors may include a substrateincluding a first photoelectric conversion element, a secondphotoelectric conversion element, a third photoelectric conversionelement, and a fourth photoelectric conversion element, a firstmicrolens at least partially overlapping both the first photoelectricconversion element and the second photoelectric conversion element in aplan view, a second microlens at least partially overlapping both thethird photoelectric conversion element and the fourth photoelectricconversion element in the plan view and a floating diffusion region. Theimage sensors may also include a first transfer gate configured tocontrol transfer of charges generated in the first photoelectricconversion element to the floating diffusion region, a second transfergate configured to control transfer of charges generated in the secondphotoelectric conversion element to the floating diffusion region, athird transfer gate configured to control transfer of charges generatedin the third photoelectric conversion element to the floating diffusionregion, a fourth transfer gate configured to control transfer of chargesgenerated in the fourth photoelectric conversion element to the floatingdiffusion region, a reset transistor and a driving transistor connectedto the floating diffusion region, and a selection transistor connectedto the driving transistor. One of the reset transistor, the drivingtransistor, and the selection transistor may include a plurality oftransistors.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present inventiveconcept will become more apparent by describing in detail exampleembodiments thereof with reference to the attached drawings, in which:

FIG. 1 is a block diagram of an image sensor according to someembodiments of the present inventive concept;

FIG. 2 is a conceptual diagram illustrating an image sensor according tosome embodiments of the present inventive concept;

FIG. 3 is an example layout diagram illustrating an image sensoraccording to some embodiments of the present inventive concept;

FIGS. 4 to 6 are circuit diagrams of the layout shown in FIG. 3according to some embodiments of the present inventive concept;

FIGS. 7 to 9 are example layout diagrams illustrating the arrangement ofpixel transistors of an image sensor according to some embodiments ofthe present inventive concept;

FIG. 10 is an example layout diagram illustrating an image sensoraccording to some embodiments of the present inventive concept;

FIGS. 11 to 13 are circuit diagrams of the layout shown in FIG. 10according to some embodiments of the present inventive concept;

FIGS. 14 to 17 are example layout diagrams illustrating the arrangementof pixel transistors of an image sensor according to some embodiments ofthe present inventive concept;

FIGS. 18A and 18B are example layout diagrams illustrating an imagesensor according to some embodiments of the present inventive concept;

FIGS. 19 to 21 are circuit diagrams of the layout shown in FIG. 18Aaccording to some embodiments of the present inventive concept;

FIGS. 22 to 25 are example layout diagrams illustrating the arrangementof pixel transistors of an image sensor according to some embodiments ofthe present inventive concept;

FIG. 26 is an example layout diagram illustrating an image sensoraccording to some embodiments of the present inventive concept;

FIGS. 27 to 29 are circuit diagrams of the layout shown in FIG. 26according to some embodiments of the present inventive concept;

FIGS. 30 and 31 are example layout diagrams illustrating the arrangementof pixel transistors of an image sensor according to some embodiments ofthe present inventive concept;

FIG. 32 is an example layout diagram illustrating an image sensoraccording to some embodiments of the present inventive concept;

FIGS. 33 to 35 are circuit diagrams of the layout shown in FIG. 32according to some embodiments of the present inventive concept; and

FIGS. 36 and 37 are example layout diagrams illustrating the arrangementof pixel transistors of an image sensor according to some embodiments ofthe present inventive concept.

DETAILED DESCRIPTION

Hereinafter, an image sensor according to some embodiments of thepresent inventive concept will be described with reference to FIGS. 1and 2 .

Referring to FIG. 1 , an image sensor according to some embodimentsincludes an active pixel sensor array 10, a row decoder 20, a row driver30, a column decoder 40, a timing generator 50, a correlated doublesampler (CDS) 60, an analog to digital converter (ADC) 70, and aninput/output buffer (I/O buffer) 80.

The active pixel sensor array 10 includes a plurality of unit pixelsarranged two-dimensionally, and may convert an optical signal into anelectrical signal. The active pixel sensor array 10 may be driven by aplurality of driving signals such as a pixel selection signal, a resetsignal and a charge transfer signal received from the row driver 30. Theelectrical signal converted by the active pixel sensor array 10 may alsobe provided to the correlated double sampler 60.

The row driver 30 may provide a plurality of driving signals to drivingthe plurality of unit pixels of the active pixel sensor array 10according to the decoding result of the row decoder 20. When the unitpixels are arranged in a matrix form, driving signals may be providedfor each row. The timing generator 50 may provide a timing signal and acontrol signal to the row decoder 20 and the column decoder 40. Thecorrelated double sampler (CDS) 60 may receive, hold and sample theelectrical signal generated by the active pixel sensor array 10. Thecorrelated double sampler 60 may doubly sample a specific noise leveland a signal level of the electrical signal to output a difference levelcorresponding to a difference between the noise level and the signallevel. The analog to digital converter (ADC) 70 may convert an analogsignal corresponding to the difference level outputted from thecorrelated double sampler 60 into a digital signal and output thedigital signal. The input/output buffer 80 may latch the digital signal,and output the latched signal as a digital signal to an image signalprocessor (not shown) sequentially according to the decoding result ofthe column decoder 40.

Referring to FIG. 2 , for example, a peripheral circuit region II may bea region where the correlated double sampler 60, the analog to digitalconverter 70 and the like of FIG. 1 may be formed. A sensor array regionI may be, for example, a region where the active pixel sensor array 10of FIG. 1 is formed. In some embodiments, the peripheral circuit regionII may be formed so as to surround the sensor array region I asillustrated in FIG. 2 , but the present inventive concept is not limitedthereto.

Hereinafter, an image sensor according to some embodiments of thepresent inventive concept will be described with reference to FIG. 1through FIG. 9 . For brevity and clarity of explanation, repeateddescriptions may be omitted.

FIGS. 3, 4, 5 and 6 are views showing one unit pixel of the sensor arrayregion I of FIG. 2 .

Referring to FIGS. 2 and 3 , the image sensor according to someembodiments of the present inventive concept may include a unit pixelincluding first, second, third and to fourth regions R1, R2, R3 and R4disposed in the substrate 100. A plurality of unit pixels, each of whichmay include the first, second, third and to fourth regions R1, R2, R3andR4 of FIG. 3 , may be arranged in the sensor array region I of FIG. 2. In some embodiments, the plurality of unit pixels may be repeatedlyarranged along a first direction D1 and a second direction D2 in thesensor array region I of FIG. 2 . The second direction D2 may traversethe first direction D1. In some embodiments, the second direction may besubstantially perpendicular to the first direction D1. Here, the unitpixel may include first, second and third pixel transistors, which willbe described later, shared by the first through fourth regions R1through R4. In some embodiments, the first direction D1 and the seconddirection D2 are horizontal directions substantially parallel to asurface of the substrate.

In some embodiments, the first to fourth regions R1 to R4 of the unitpixel may be arranged as illustrated in FIG. 3 . Specifically, thesecond region R2 may be disposed adjacent to the first region R1 in thefirst direction D1. The third region R3 may be disposed adjacent to thefirst region R1 in the second direction D2. The fourth region R4 may bedisposed adjacent to the third region R3 in the first direction D1 andmay be disposed adjacent to the second region R2 in the second directionD2.

Still referring to FG. 3, in some embodiments, a first microlens ML1 maybe disposed to overlap both the first region R1 and the second region R2in a plan view and may be spaced apart from both the first region R1 andthe second region R2 in a third direction D3. The third direction D3 maybe a vertical direction and may be substantially perpendicular to boththe first direction D1 and the second direction D2. In other words, thefirst region R1 and the second region R2 may share the single microlens(i.e., first microlens ML1). The first micro lens ML1 may provide lightto a first photoelectric conversion element PD1 and a secondphotoelectric conversion element PD2.

A second microlens ML2 may be disposed to overlap both the third regionR3 and the fourth region R4 in the plan view and may be spaced apartfrom both the third region R3 and the fourth region R4 in the thirddirection D3. In other words, the third region R3 and the fourth regionR4 may share the single microlens (i.e., second microlens ML2). Thesecond microlens ML2 may provide light to a third photoelectricconversion element PD3 and a fourth photoelectric conversion elementPD4.

The first region R1 may include a first pixel region PR1 and a firstpixel region LR1. In some embodiments, the first pixel region PR1 andthe first pixel region LR1 may be different each other and thus may notbe overlap each other as illustrated in FIG. 3 . The first pixel regionPR1 may include the first photoelectric conversion element PD1 and afirst transfer gate TG1. In the first pixel region LR1, at least one ofthe pixel transistors, which will be described later, may be disposed.However, the present inventive concept is not limited thereto. In someembodiments, no pixel transistor may be disposed in the first pixelregion LR1. Similar to the first region R1, the second, third and fourthregions R2, R3 and R4 may include second, third and fourth pixel regionsPR2, PR3 and PR4, respectively, and second, third and fourth pixelregions LR2, LR3, and LR4, respectively, as illustrated in FIG. 3 . Thesecond, third and fourth pixel regions PR2, PR3 and PR4 may include thesecond, third and fourth photoelectric conversion elements PD2, PD3 andPD4, respectively, and second, third and fourth transfer gates TG2, TG3,and TG4, respectively. In the second to fourth pixel regions LR2 to LR4,at least one of the pixel transistors may be disposed. However, thepresent inventive concept is not limited thereto, and pixel transistorsmay not be disposed in some regions of the second to fourth pixelregions LR2 to LR4.

In some embodiments, the first microlens ML1 may at least partiallyoverlap both the first photoelectric conversion element PD1 and thesecond photoelectric conversion element PD2, as illustrated in FIG. 3 ,and the first microlens ML1 may be spaced part from the firstphotoelectric conversion element PD1 and the second photoelectricconversion element PD2 in the third direction D3. In some embodiments,the second microlens ML2 may at least partially overlap both the thirdphotoelectric conversion element PD3 and the fourth photoelectricconversion element PD4, as illustrated in FIG. 3 , and, the secondmicrolens ML2 may be spaced part from the third photoelectric conversionelement PD3 and the fourth photoelectric conversion element PD4 in thethird direction D3. Although FIG. 3 shows that that a single microlensis disposed to overlap two photoelectric conversion elements, thepresent inventive concept is not limited thereto. The number ofphotoelectric conversion elements overlapped by a single microlens mayvary, for example, three, four, five, six or more. It will be understoodthat a single microlens may overlap an arbitrary number of photoelectricconversion elements in the plan view.

The first to fourth photoelectric conversion elements PD1, PD2, PD3 andPD4 may include, for example, a photodiode, a photo transistor, a photogate, a pinned photodiode (PPD), an organic photodiode (OPD), a quantumdot (QD), and a combination thereof, and may generate and/or provideelectrical charges (e.g., electrons, holes) in response to incidentlight.

The first to fourth pixel regions PR1 to PR4 may include the first tofourth transfer gates TG1 to TG4, respectively. Although FIG. 3illustrates that the first to fourth transfer gates TG1 to TG4 arerespectively disposed in contact with the first to fourth photoelectricconversion elements PD1 to PD4, the present inventive concept is notlimited thereto. It will be understood that the first to fourth transfergates TG1 to TG4 may be disposed at arbitrary positions in the first tofourth regions R1 to R4, respectively.

Still referring to FIG. 3 , a floating diffusion region FD may bedisposed adjacent to the first to fourth transfer gates TG1 to TG4. Forexample, the first to fourth transfer gates TG1 to TG4 may be gates offirst to fourth transfer transistors, respectively, and the floatingdiffusion region FD may be a source/drain region of each of the first tofourth transfer transistors TG1 to TG4.

The first to fourth transfer transistors TG1 to TG4 may share the singlefloating diffusion region FD. Although FIG. 3 illustrates the floatingdiffusion region FD disposed adjacent to the first to fourth transfergates TG1 to TG4 as a single region, the present inventive concept isnot limited thereto. In some embodiments, the floating diffusion regionFD may include four separate regions respectively corresponding to thefirst to fourth transfer gates TG1 to TG4 so as to be adjacent to thefirst to fourth transfer gates TG1 to TG4. In this case, the fourfloating diffusion regions may be spaced apart from each other, but theymay be electrically connected to each other through wiring or the liketo constitute the floating diffusion region FD.

Referring to FIGS. 3 and 4 , an image sensor according to someembodiments of the present inventive concept may include first to thirdpixel transistors SF, RG and SEL. Each of the first to third pixeltransistors SF, RG and SEL may be disposed in at least one of the firstto fourth pixel regions LR1 to LR4. In some embodiments, a plurality offirst pixel transistors may be provided. The first to third pixeltransistors SF, RG and SEL may perform different functions.

Specifically, the first and second photoelectric conversion elements PD1and PD2 may receive light through the first microlens ML1 and maygenerate first and second signals. The first and second signals maycorrespond to electrical charges (e.g., photoelectric charges) generatedin the first and second photoelectric conversion elements PD1 and PD2 inresponse to incident light. In some embodiment, the first and secondsignals may be in proportion to the amount of the incident light.Further, the third and fourth photoelectric conversion elements PD3 andPD4 may receive light through the second microlens ML2 and may generatethird and fourth signals. The third and fourth signals may correspond toelectrical charges (e.g., photoelectric charges) generated in the thirdand fourth photoelectric conversion elements PD3 and PD4 in response toincident light. In some embodiment, the third and fourth photoelectricconversion elements PD3 and PD4 may be in proportion to the amount ofthe incident light. The first to fourth signals may be provided to thefloating diffusion region FD through the first to fourth transfer gatesTG1 to TG4. In some embodiments, complementary signals may be applied tothe first to fourth transfer gates TG1 to TG4, respectively, and any oneof the first to fourth signals may be provided to the floating diffusionregion FD according to first, second, third and fourth transmissioncontrol signals TX1, Tx2, TX3 and TX4.

The floating diffusion region FD may receive any one of the first tofourth signals generated by the first to fourth photoelectric conversionelements PD1 to PD4 and may cumulatively store it. The first to fourthtransfer gates TG1 to TG4 may control transfer of the first to fourthsignals to the floating diffusion region FD in response to the first,second, third and fourth transmission control signals TX1, Tx2, TX3 andTX4.

In FIG. 4 , SF may be a driving transistor that may be controlled by thefloating diffusion region FD to generate an output voltage. Thetransistor SF may be electrically connected to the floating diffusionregion FD as illustrated in FIG. 4 . The transistor SF may be combinedwith a current source (e.g., a constant current source) located outsidethe unit pixel to serve as a source follower buffer amplifier, mayamplify a potential change in the floating diffusion region FD and maygenerate an output voltage Vout. The output voltage Vout may beoutputted to the transistor SEL. RG may be a reset transistor that maybe controlled by a reset control signal RX and may reset the floatingdiffusion region FD to VDD. The transistor RG may be electricallyconnected to the floating diffusion region FD as illustrated in FIG. 4 .SEL may be a selection transistor whose drain node may be connected tothe source node of the transistor SF, and the transistor SEL may becontrolled by a selection signal SX and may output the output voltageVout to a column line CL connected to the unit pixel.

The first to fourth transmission control signals TX1 to TX4, the resetcontrol signal RX and the selection signal SX may be outputted from therow driver 30 of FIG. 1 .

In some embodiments, the unit pixel including the first to fourthregions R1 to R4 may include multiple driving transistors SF1 and SF2 asthe plurality of first pixel transistors, as illustrated in FIG. 4 . Thesecond pixel transistor may be the reset transistor RG, and the thirdpixel transistor may be the selection transistor SEL.

The first pixel transistors SF1 and SF2 may be connected to each otherin parallel as illustrated in FIG. 4 . For example, the drain node ofeach of the first pixel transistors SF1 and SF2 may be connected to VDD,and the source node of each of the first pixel transistors SF1 and SF2may be connected to the third pixel transistor SEL and may be controlledby the floating diffusion region FD.

In the image sensor according to some embodiments of the presentinventive concept, the plurality of first pixel transistors SF1 and SF2serving as driving transistors may be disposed in at least one of thefirst to fourth pixel regions LR1 to LR4, thereby improving thecharacteristics of pixels of the unit pixel and the read performance,and making the unit pixel strong against noise.

Referring to FIGS. 3 and 5 , in some embodiments, the unit pixelincluding the first to fourth regions R1 to R4 may include multipleselection transistors SEL1 and SEL2 as the plurality of first pixeltransistors as illustrated in FIG. 5 . The second pixel transistor maybe the driving transistor SF and the third pixel transistor may be thereset transistor RG. Hereinafter, differences from those described withreference to FIGS. 3 and 4 will be mainly described.

The first pixel transistors SEL1 and SEL2 may be connected to each otherin parallel as illustrated in FIG. 5 . For example, the drain node ofeach of the first pixel transistors SEL1 and SEL2 may be connected tothe source node of the second pixel transistor SF, and the source nodesof the first pixel transistors SEL1 and SEL2 may be connected to columnlines CL1 and CL2, respectively. Further, each of the first pixeltransistors SEL1 and SEL2 may be controlled by first and secondselection signals SX1 and SX2, which may be complementary to each other.The first pixel transistors SEL1 and SEL2 may selectively output theoutput voltage Vout generated by the second pixel transistor SF to thecolumn lines CL1 and CL2. In some embodiments, only one of the firstpixel transistors SEL1 and SEL2 may output the output voltage Vout at atime.

In the image sensor according to some embodiments of the presentinventive concept, the plurality of first pixel transistors SEL1 andSEL2 serving as selection transistors may be disposed in at least one ofthe first to fourth pixel regions LR1 to LR4, thereby improving theflexibility of binning.

Referring to FIGS. 3 and 6 , the unit pixel including the first tofourth regions R1 to R4 may include multiple reset transistors RG1 andRG2 as the plurality of first pixel transistors, as illustrated in FIG.6 . The second pixel transistor may be the driving transistor SF and thethird pixel transistor may be the selection transistor SEL. Hereinafter,differences from those described with reference to FIGS. 3 and 4 will bemainly described.

The first pixel transistors RG1 and RG2 may be connected to each otherin series as illustrated in FIG. 6 . For example, the drain node of onetransistor RG1 of the first pixel transistors RG1 and RG2 may beconnected to VDD, and the source node of the transistor RG1 may beconnected to the drain node of the other transistor RG2 of the firstpixel transistors RG1 and RG2. The source node of the other transistorRG2 of the first pixel transistors RG1 and RG2 may be connected to thefloating diffusion region FD. In addition, each of the first pixeltransistors RG1 and RG2 may be controlled by first and second resetcontrol signals RX1 and RX2.

In the image sensor according to some embodiments of the presentinventive concept, the plurality of first pixel transistors RG1 and RG2serving as reset transistors may be disposed in at least one of thefirst to fourth pixel regions LR1 to LR4, thereby improving thesensitivity of the image sensor by increasing a conversion gain.

Referring to FIGS. 4 to 7 , the plurality of first pixel transistors mayinclude fourth and fifth pixel transistors. The fourth pixel transistormay be disposed, for example, in the second pixel region LR2. Further,the fifth pixel transistor may be disposed, for example, in either thefirst pixel region LR1 or in the second pixel region LR2.

For example, if the fifth pixel transistor is disposed in the firstpixel region LR1, the fifth pixel transistor may be either TR71 or TR72.In some embodiments, if the fifth pixel transistor is disposed in thesecond pixel region LR2, one of TR73 and TR74 may be the fourth pixeltransistor, and the other one of TR73 and TR74 may be the fifth pixeltransistor.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 4 , the fourth pixel transistorSF1 may be TR71 and the fifth pixel transistor SF2 may be TR73. Forexample, if the plurality of first pixel transistors are selectiontransistors SEL1 and SEL2 as shown in FIG. 5 , the fourth pixeltransistor SEL1 may be TR71 and the fifth pixel transistor SEL2 may beTR74. For example, if the plurality of first pixel transistors are resettransistors RG1 and RG2 as shown in FIG. 6 , the fourth pixel transistorRG1 may be TR73 and the fifth pixel transistor RG2 may be TR74.

Referring to FIGS. 4, 5, 6 and 8 , the fourth pixel transistor may bedisposed, for example, in the second pixel region LR2. The fifth pixeltransistor may be disposed to overlap, for example, a portion of thefirst pixel region LR1 and a portion of the second pixel region LR2. Insome embodiments, the fifth pixel transistor may be disposed to overlap,for example, a portion of the second pixel region LR2 and a portion ofthe fourth pixel region LR4.

If the fifth pixel transistor is disposed to overlap a portion of thefirst pixel region LR1 and a portion of the second pixel region LR2, thefifth pixel transistor may be TR82. If the fifth pixel transistor isdisposed to overlap a portion of the second pixel region LR2 and aportion of the fourth pixel region LR4, the fifth pixel transistor maybe TR84.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 4 , the fourth pixel transistorSF1 may be TR81 and the fifth pixel transistor SF2 may be TR83. Forexample, if the plurality of first pixel transistors are selectiontransistors SEL 1 and SEL 2 as shown in FIG. 5 , the fourth pixeltransistor SEL1 may be TR83 and the fifth pixel transistor SEL2 may beTR81. For example, if the plurality of first pixel transistors are resettransistors RG1 and RG2 as shown in FIG. 6 , the fourth pixel transistorRG1 may be TR83 and the fifth pixel transistor RG2 may be TR84.

Referring to FIGS. 4, 5, 6 and 9 , the fourth pixel transistor may bedisposed, for example, in the second pixel region LR2. Further, thefifth pixel transistor may be disposed, for example, in either thesecond pixel region LR2 or the fourth pixel region LR4.

For example, if the fifth pixel transistor is disposed in the secondpixel region LR2, one of TR91 and TR92 may be the fourth pixeltransistor, and the other one of TR91 and TR92 may be the fifth pixeltransistor. On the other hand, if the fifth pixel transistor is disposedin the fourth pixel region LR4, the fourth pixel transistor may be anyone of TR91 and TR92, and the fifth pixel transistor may be any one ofTR93 and TR94.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 4 , the fourth pixel transistorSF1 may be TR91, and the fifth pixel transistor SF2 may be TR93. Forexample, if the plurality of first pixel transistors are selectiontransistors SEL1 and SEL 2 as shown in FIG. 5 , the fourth pixeltransistor SEL1 may be TR91, and the fifth pixel transistor SEL2 may beTR94. For example, if the plurality of first pixel transistors are resettransistors RG1 and RG2 as shown in FIG. 6 , the fourth pixel transistorRG1 may be TR91, and the fifth pixel transistor RG2 may be TR92.

Hereinafter, an image sensor according to some embodiments of thepresent inventive concept will be described with reference to FIGS. 2through 6 and 10 through 17 . For brevity and clarity of explanation, arepeated description may be omitted.

FIG. 10 and FIGS. 14 through 17 are views showing a single unit pixel ofthe sensor array region I of FIG. 2 according to some embodiments of thepresent inventive concept.

Referring to FIGS. 2, 3 and 10 , the image sensor according to someembodiments of the present inventive concept may include a unit pixelincluding first, second, third, fourth, fifth, sixth, seventh and eighthregions R1, R2, R3, R4, R5, R6, R7, and R8 disposed in the substrate100. A plurality of unit pixels, each of which includes first througheight regions R1 to R8 of FIG. 10 , may be arranged in the sensor arrayregion I of FIG. 2 . In this case, the plurality of unit pixels may berepeatedly arranged along the first direction D1 and the seconddirection D2 in the sensor array region I of FIG. 2 .

The first to fourth regions R1 to R4 in FIG. 10 may be substantially thesame as those described with reference to FIG. 3 .

In some embodiments, the fifth, sixth, seventh and eighth regions R5,R6, R7 and R8 may be arranged in the substrate 100 as illustrated inFIG. 10 . The fifth region R5 may be disposed adjacent to the thirdregion R3 in the second direction D2. The sixth region R6 may bedisposed adjacent to the fifth region R5 in the first direction D1 andmay be disposed adjacent to the fourth region R4 in the second directionD2. The seventh region R7 may be disposed adjacent to the fifth regionR5 in the second direction D2. The eighth region R8 may be disposedadjacent to the seventh region R7 in the first direction D1 and may bedisposed adjacent to the sixth region R6 in the second direction D2.

A third microlens ML3 may be disposed to overlap both the fifth regionR5 and the sixth region R6 in a plan view and may be spaced apart fromthe fifth region R5 and the sixth region R6 in the third direction D3.In other words, the fifth region R5 and the sixth region R6 may share asingle microlens (i.e., third microlens ML3). The third microlens ML3may provide light to a fifth photoelectric conversion element PD5 and asixth photoelectric conversion element PD6.

A fourth microlens ML4 may be disposed to overlap both the seventhregion R7 and the eighth region R8 in a plan view and may be spacedapart from the seventh region R7 and the eighth region R8 in the thirddirection D3. In other words, the seventh region R7 and the eighthregion R8 may share a single microlens (i.e., fourth microlens ML4). Thefourth micro lens ML4 may provide light to a seventh photoelectricconversion element PD7 and an eighth photoelectric conversion elementPD8.

The fifth region R5 may include a fifth pixel region PR5 and a fifthpixel region LR5. The fifth pixel region PR5 may include the fifthphotoelectric conversion element PD5 and a fifth transfer gate TG5. Insome embodiments, in the fifth pixel region LR5, at least one of theabove-described pixel transistors may be disposed. However, the presentinventive concept is not limited thereto. For example, no pixeltransistor may be disposed in the fifth pixel region LR5.

Similar to the fifth region R5, the sixth to eighth regions R6 to R8 mayinclude sixth, seventh and eighth pixel regions PR6, PR7 and PR8 andsixth, seventh and eighth pixel regions LR, LR7 and LR8, respectively.The sixth to eighth pixel regions PR6 to PR8 may include the sixth,seventh and eighth photoelectric conversion elements PD6, PD7 and PD8,respectively, and sixth, seventh and eighth transfer gates TG6, TG7 andTG8, respectively. In some embodiments, in the sixth to eighth pixelregions LR6 to LR8, at least one of the above-described pixeltransistors may be disposed. However, the present inventive concept isnot limited thereto, and no pixel transistors may be disposed in someregions of the sixth to eighth pixel regions LR6 to LR8. In someembodiments, the fifth, sixth, seventh, and eighth pixel regions PR5 toPR8 may be different from the fifth, sixth, seventh, and eighth pixelregions LR5 to LR8, respectively, and may not overlap the fifth, sixth,seventh, and eighth pixel regions LR5 to LR8, respectively. For example,the fifth pixel region PR5 may not overlap the fifth pixel region LR5,as illustrated in FIG. 10 .

The third microlens ML3 may at least partially overlap both the fifthphotoelectric conversion element PD5 and the sixth photoelectricconversion element PD6 and may be spaced part from the fifthphotoelectric conversion element PD5 and the sixth photoelectricconversion element PD6 in the third direction D3. The fourth microlensML4 may at least partially overlap both the seventh photoelectricconversion element PD7 and the eighth photoelectric conversion elementPD8 and may be spaced part from the seventh photoelectric conversionelement PD7 and the eighth photoelectric conversion element PD8 in thethird direction D3.

Each of the fifth to eighth photoelectric conversion elements PD5 to PD8may be substantially the same as, for example, one of the first tofourth photoelectric conversion elements PD1 to PD4.

The fifth to eighth pixel regions PR5 to PR8 may include the fifth,sixth, seventh and eighth transfer gates TG5, TG6, TG7 and TG8. AlthoughFIG. 10 illustrates that the fifth to eighth transfer gates TG5 to TG8are respectively disposed in contact with the fifth to eighthphotoelectric conversion elements PD5 to PD8, the present inventiveconcept is not limited thereto. In other words, in some embodiments, thefifth to eighth transfer gates TG5 to TG8 may be disposed at arbitrarypositions in the fifth to eighth regions R5 to R8, respectively.

Still referring to FIG. 10 , the floating diffusion region FD mayinclude a first floating diffusion region FD1 disposed adjacent to thefirst to fourth transfer gates TG1 to TG4 and a second floatingdiffusion region FD2 disposed adjacent to the fifth to eighth transfergates TG5 to TG8. The first floating diffusion region FD1 may be asource/drain region of each of the first to fourth transfer transistors.For example, the fifth to eighth transfer gates TG5 to TG8 may berespective gates of fifth to eighth transfer transistors, and the secondfloating diffusion region FD2 may be a source/drain region of each ofthe fifth to eighth transfer transistors TG5 to TG8.

The first floating diffusion region FD1 and the second floatingdiffusion region FD2 may be electrically connected to each other. Inother words, the first to eighth transfer transistors may share thefloating diffusion region FD. It will be understood that the firstfloating diffusion region FD1 and the second floating diffusion regionFD2 may be collectively considered as a single floating diffusion regionFD when the first and second diffusion regions FD1 and FD2 areelectrically connected to each other.

The fifth and sixth photoelectric conversion elements PD5 and PD6 mayreceive light through the third microlens ML3 and may generate fifth andsixth signals that may correspond to photoelectric charges generated inthe fifth and sixth photoelectric conversion elements PD5 and PD6 inresponse to incident light. In some embodiments, the fifth and sixthsignals may be in proportion to the amount of incident light. Theseventh and eighth photoelectric conversion elements PD7 and PD8 mayreceive light through the fourth microlens ML4 and may generate seventhand eighth signals that may correspond to photoelectric charges inresponse to incident light. In some embodiments, the seventh and eighthsignals may be in proportion to the amount of incident light.

The first to eighth signals may be provided to the floating diffusionregion FD through the first to eighth transfer gates TG1 to TG8. In thiscase, complementary signals may be applied to the first to eighthtransfer gates TG1 to TG8, respectively, and any one of the first,second, third, fourth, fifth, sixth, seventh and eighth signals may beprovided to the floating diffusion region FD according to first, second,third, fourth, fifth, sixth, seventh and eighth transmission controlsignals TX1, TX2, TX3, TX4, TX5, TX6, TX7, and TX8. The floatingdiffusion region FD may receive any one of the first to eighth signalsgenerated by the first to eighth photoelectric conversion elements PD1to PD8 and may cumulatively store it.

In the following description, pixel transistors SF, SEL and RG in FIGS.11 to 13 may be substantially the same as the pixel transistors SF, SELand RG discussed with reference to FIGS. 4 to 6 .

Referring to FIGS. 10 and 11 , the image sensor according to someembodiments of the present inventive concept may include first to thirdpixel transistors SF, RG and SEL. Each of the first to third pixeltransistors SF, RG and SEL may be disposed in at least one of the firstto eighth pixel regions LR1 to LR8.

In some embodiments, the unit pixel including the first to eighthregions R1 to R8 may include two driving transistors SF1 and SF2 as theplurality of first pixel transistors.

Referring to FIGS. 10 and 12 , in some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include two selectiontransistors SEL1 and SEL2 as the plurality of first pixel transistors.

Referring to FIGS. 10 and 13 , in some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include two resettransistors RG1 and RG2 as the plurality of first pixel transistors.

In some embodiments, the plurality of first pixel transistors mayinclude a fourth pixel transistor and a fifth pixel transistor.Referring to FIGS. 11 to 14 , the fourth pixel transistor may bedisposed, for example, in either the first pixel region LR1 or the fifthpixel region LR5. The fifth pixel transistor may be disposed, forexample, in any one of the second pixel region LR2, the fifth pixelregion LR5 and the sixth pixel region LR6. For example, if the fourthpixel transistor is disposed in the first pixel region LR1, the fourthpixel transistor may be TR141. In this case, the fifth pixel transistormay be, for example, any one of TR142, TR143 and TR144. In someembodiments, when the fourth pixel transistor is disposed in the fifthpixel region LR5, the fourth pixel transistor may be TR143. In thiscase, the fifth pixel transistor may be any one of TR141, TR142 andTR144.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 11 , the fourth pixeltransistor SF1 may be TR141, and the fifth pixel transistor SF2 may beTR142. In some embodiments, the fourth pixel transistor SF1 may beTR143, and the fifth pixel transistor SF2 may be TR144. For example, ifthe plurality of first pixel transistors are selection transistors SEL1and SEL 2 as shown in FIG. 12 , the fourth pixel transistor SEL1 may beTR141, and the fifth pixel transistor SEL2 may be TR142. In someembodiments, the fourth pixel transistor SEL1 may be TR143, and thefifth pixel transistor SEL2 may be TR142. For example, if the pluralityof first pixel transistors are reset transistors RG 1 and RG2 as shownin FIG. 13 , the fourth pixel transistor RG1 may be TR141, and the fifthpixel transistor RG2 may be TR142. In some embodiments, the fourth pixeltransistor RG1 may be TR141, and the fifth pixel transistor RG2 may beTR143.

Referring to FIGS. 11 to 13 and 15 , the fourth pixel transistor may bedisposed, for example, in the fourth pixel region LR4. Further, thefifth pixel transistor may be disposed, for example, in either thefourth pixel region LR4 or the sixth pixel region LR6. For example, thefourth pixel transistor may be TR151. The fifth pixel transistor may beany one of TR152, TR153 and TR154.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 11 , the fourth pixeltransistor SF1 may be TR151, and the fifth pixel transistor SF2 may beTR152. For example, if the plurality of first pixel transistors areselection transistors SEL 1 and SEL 2 as shown in FIG. 12 , the fourthpixel transistor SEL1 may be TR151, and the fifth pixel transistor SEL2may be TR154. For example, if the plurality of first pixel transistorsare reset transistors RG1 and RG2 as shown in FIG. 13 , the fourth pixeltransistor RG1 may be TR151, and the fifth pixel transistor RG2 may beTR152.

Although FIGS. 11, 12 and 13 illustrate that two pixel transistors areprovided for each type, this is only for convenience of description andillustration, and the present inventive concept is not limited thereto.For example, referring to FIG. 16 , the plurality of first pixeltransistors may further a sixth pixel transistor, and therefore mayinclude the fourth, fifth and sixth pixel transistors. For example, ifthe plurality of first pixel transistors are driving transistors, thefourth to sixth pixel transistors may be TR163, TR164 and TR165,respectively. In this case, the fourth to sixth pixel transistors may beconnected in parallel with each other. Further, referring to FIG. 17 ,if the plurality of first pixel transistors are driving transistors, thefourth to sixth pixel transistors may be TR171, TR172 and TR173.

Hereinafter, an image sensor according to some embodiments of thepresent inventive concept will be described with reference to FIGS. 2through 10 , FIGS. 18A, 18B, and 19 through 25 . For brevity and clarityof explanation, repeated descriptions may be omitted.

FIGS. 18A, 18B and 22 to 25 are views showing a single unit pixel of thesensor array region I of FIG. 2 .

Referring to FIGS. 2, 3, 10, 18A and 18B, the first to fourth regions R1to R4 in FIG. 10A may be substantially the same as those discussed withreference to FIG. 3 .

In some embodiments, the fifth, sixth, seventh and eighth regions R5,R6, R7 and R8 may be arranged in the substrate 100, as illustrated inFIG. 18A. The fifth region R5 may be disposed adjacent to the secondregion R2 in the first direction D1. The sixth region R6 may be disposedadjacent to the fifth region R5 in the first direction D1. The seventhregion R7 may be disposed adjacent to the fourth region R4 in the firstdirection D1 and may be disposed adjacent to the fifth region R5 in thesecond direction D2. The eighth region R8 may be disposed adjacent tothe seventh region R7 in the first direction D1 and may be disposedadjacent to the sixth region R6 in the second direction D2.

The components included in the fifth to eighth regions R5 to R8 may besubstantially the same as those described with reference to FIG. 10 .

In some embodiments, a single color filter CF may be disposed betweenthe first to eighth regions R1 to R8 and the first to fourth microlensesML1 to ML4.

For example, referring to FIG. 18B, the first to eighth regions R1 to R8in FIG. 18B may be substantially the same as the unit pixel R1 to R8 ofthe image sensor shown in FIG. 18A. In FIG. 18B, if the unit pixelincluding the first to eighth regions R1 to R8 of the image sensor shownin FIG. 18A is referred to as a first unit pixel, a second unit pixelincluding the ninth to sixteenth regions R9 to R16 may be disposedadjacent to the first unit pixel in the second direction D2. Also, athird unit pixel including the seventeenth to twenty-fourth regions R17to R24 may be disposed adjacent to the first unit pixel in the firstdirection D1. Further, a fourth unit pixel including the twenty-fifth tothirty-second regions R25 to R32 may be disposed adjacent to the secondunit pixel including ninth to sixteenth regions R9 to R16 in the firstdirection D1. Each of the second to fourth unit pixels may besubstantially the same as the first unit pixel.

Each of the first to fourth unit pixels may include a plurality oftransistors of at least one type of a driving transistor, a resettransistor and a selection transistor.

In some embodiments, a single color filter may be disposed between thefirst to eighth regions R1 to R8 and the first to fourth microlenses ML1to ML4 and may be referred to as a first color filter CF1. That is, thefirst to eighth regions R1 to R8 may share the first color filter CF1.In some embodiments, a second color filter CF2, which is a single colorfilter, may be disposed between the ninth to sixteenth regions R9 to R16and fifth to eighth microlenses ML5 to ML8. That is, the ninth tosixteenth regions R9 to R16 may share the second color filter CF2.Further, a third color filter CF3, which is a single color filter, maybe disposed between the seventeenth to twenty-fourth regions R17 to R24and ninth to twelfth microlenses ML9 to ML12. That is, the seventeenthto twenty-fourth regions R17 to R24 may share the third color filterCF3. Furthermore, a fourth color filter CF4, which is a single colorfilter, may be disposed between the twenty-fifth to thirty-secondregions R25 to R32 and thirteenth to sixteenth microlenses ML13 to ML16.That is, the twenty-fifth to thirty-second regions R25 to R32 may sharethe fourth color filter CF4.

The first to fourth color filters CF1 to CF4 may pass different colors,respectively. However, the present inventive concept is not limitedthereto. For example, it will be understood that some of the first tofourth color filters CF1 to CF4 may pass the same color. For example,the first color filter CF1 may be a color filter that passes blue-basedcolors. The second and third color filters CF2 and CF3 may be colorfilters that pass green-based colors. The fourth color filter CF4 may bea color filter that passes red-based colors.

The present inventive concept is not limited to the shape of the colorfilters (CF1, CF2, CF3, CF4) in the FIGS. 18A and 18B, but is onlyschematically represented. The color filters of various shapes can beapplied.

The pixel transistors SF, SEL and RG in FIGS. 19 to 21 may besubstantially the same as the pixel transistors SF, SEL and RG describedwith reference to FIGS. 4 to 6 .

Referring to FIGS. 18A and 19 , the image sensor according to someembodiments of the present inventive concept may include first to thirdpixel transistors SF, RG and SEL. In some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include drivingtransistors SF1 and SF2 as the plurality of first pixel transistors.

Referring to FIGS. 18A and 20 , in some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include selectiontransistors SEL1 and SEL2 as the plurality of first pixel transistors.

Referring to FIGS. 18A and 21 , in some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include resettransistors RG1 and RG2 as the plurality of first pixel transistors.

In some embodiments the plurality of first pixel transistors may includea fourth pixel transistor and a fifth pixel transistor. Referring toFIGS. 19 to 22 , the fourth pixel transistor may be disposed, forexample, in the first pixel region LR1. The fifth pixel transistor maybe disposed, for example, in either the second pixel region LR2 or thesixth pixel region LR6. For example, the fourth pixel transistor may beTR221. The fifth pixel transistor may be either TR222 or TR224. One ofthe second and third pixel transistors may be TR223.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 19 , the fourth pixeltransistor SF1 may be TR221, and the fifth pixel transistor SF2 may beTR222. For example, if the plurality of first pixel transistors areselection transistors SEL1 and SEL2 as shown in FIG. 20 , the fourthpixel transistor SEL1 may be TR221, and the fifth pixel transistor SEL2may be TR224. For example, if the plurality of first pixel transistorsare reset transistors RG1 and RG2 as shown in FIG. 21 , the fourth pixeltransistor RG1 may be TR221, and the fifth pixel transistor RG2 may beTR222.

Referring to FIGS. 19 to 21 and 23 , the fourth pixel transistor may bedisposed, for example, in the sixth pixel region LR6. The fifth pixeltransistor may be disposed to overlap, for example, a portion of thesecond pixel region LR2, a portion of the fourth pixel region LR4, aportion of the fifth pixel region LR5 and a portion of the seventh pixelregion LR7. For example, the fourth pixel transistor may be TR234. Thefifth pixel transistor may be, for example, TR233.

For example, if the plurality of first pixel transistors are resettransistors RG1 and RG2 as shown in FIG. 21 , the fourth pixeltransistor RG1 may be TR234, and the fifth pixel transistor RG2 may beTR233. One of the second and third pixel transistors may be TR231.

Referring to FIGS. 19 to 21 and 24 , the fourth and fifth pixeltransistors may be disposed to overlap, for example, a portion of thesecond pixel region LR2 and a portion of the fifth pixel region LR5. Insome embodiments, the fourth and fifth pixel transistors may be disposedto overlap, for example, a portion of the fourth pixel region LR4 and aportion of the seventh pixel region LR7. For example, the fourth pixeltransistor may be TR241 and the fifth pixel transistor may be TR242. Insome embodiments, the fourth pixel transistor may be TR243 and the fifthpixel transistor may be TR244.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 19 , the fourth pixeltransistor SF1 may be TR243, and the fifth pixel transistor SF2 may beTR244. For example, if the plurality of first pixel transistors areselection transistors SEL1 and SEL2 as shown in FIG. 20 , the fourthpixel transistor SEL1 may be TR241, and the fifth pixel transistor SEL2may be TR242. For example, if the plurality of first pixel transistorsare reset transistors RG1 and RG2 as shown in FIG. 21 , the fourth pixeltransistor RG1 may be TR241, and the fifth pixel transistor RG2 may beTR242.

Although FIGS. 22 to 24 illustrate that two pixel transistors areprovided for each type, this is only for convenience of description andillustration, and the present inventive concept is not limited thereto.For example, the first pixel transistors may further include a sixthpixel transistor. The sixth pixel transistor may be disposed in any oneof the first to eighth pixel regions LR1 to LR8. For example, referringto FIG. 25 , the fourth to sixth pixel transistors may be TR251, TR252and TR253, respectively. Each of the second and third pixel transistorsmay be one of TR254, 255. In this case, the fourth to sixth pixeltransistors may be connected to each other, for example, in parallel orin series.

Hereinafter, an image sensor according to some embodiments of thepresent inventive concept will be described with reference to FIGS. 2through 6 and FIGS. 26 through 31 . For brevity and clarity ofexplanation, repeated descriptions may be omitted. FIGS. 26, 30 and 31are views showing a single unit pixel of the sensor array region I ofFIG. 2 .

Referring to FIGS. 2, 3 and 26 , the image sensor according to someembodiments of the present inventive concept may include a unit pixelincluding first to fourth regions R1 to R4 disposed in the substrate100. A plurality of unit pixels, each of which includes R1 to R4 of FIG.26 , may be arranged in the sensor array region I of FIG. 2 . In thiscase, the plurality of unit pixels may be repeatedly arranged along thefirst direction D1 and the second direction D2 in the sensor arrayregion I of FIG. 2 .

In some embodiments, the first, second, third and fourth regions R1, R2,R3 and R4 may be arranged in the substrate 100 as illustrated in FIG. 26. The second region R2 may be disposed adjacent to the first region R1in the first direction D1. The third region R3 may be disposed adjacentto the second region R2 in the first direction D1. The fourth region R4may be disposed adjacent to the third region R3 in the first directionD1. The components included in the first to fourth regions R1 to R4 inFIG. 26 may be substantially the same as those described with referenceto FIG. 3 .

The pixel transistors SF, SEL and RG in FIGS. 27 to 29 may besubstantially the same as the pixel transistors SF, SEL and RG describedwith reference to FIGS. 4 to 6 .

Referring to FIGS. 26 and 27 , the image sensor according to someembodiments of the present inventive concept may include first to thirdpixel transistors SF, RG and SEL.

In some embodiments in which the unit pixel includes the first to fourthregions R1 to R4, the plurality of first pixel transistors may be SF1and SF2 in FIG. 27 as driving transistors.

Referring to FIGS. 26 and 28 , in some embodiments, the unit pixelincluding the first to fourth regions R1 to R4 may include selectiontransistors SEL1 and SEL2 as the plurality of first pixel transistors.

Referring to FIGS. 26 and 29 , in some embodiments, the unit pixelincluding the first to fourth regions R1 to R4 may include resettransistors RG1 and RG2 as the plurality of first pixel transistors.

Referring to FIGS. 26 to 30 , the fourth pixel transistor of theplurality of first pixel transistors may be disposed, for example, ineither the first pixel region LR1 or the third pixel region LR3. Thefifth pixel transistor of the plurality of first pixel transistors maybe disposed, for example, in either the second pixel region LR2 or thefourth pixel region LR4. For example, the fourth pixel transistor may beeither TR301 or TR303. The fifth pixel transistor may be, for example,either TR302 or TR304.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 27 , the fourth pixeltransistor SF1 may be TR301, and the fifth pixel transistor SF2 may beTR302. For example, if the plurality of first pixel transistors areselection transistors SEL1 and SEL2 as shown in FIG. 28 , the fourthpixel transistor SEL1 may be TR301, and the fifth pixel transistor SEL2may be TR304. For example, if the plurality of first pixel transistorsare reset transistors RG1 and RG2 as shown in FIG. 29 , the fourth pixeltransistor RG1 may be TR303, and the fifth pixel transistor RG2 may beTR304.

Referring to FIGS. 26 to 29 and 31 , the fourth pixel transistor of theplurality of first pixel transistors may be disposed to overlap, forexample, a portion of the third pixel region LR3 and a portion of thefourth pixel region LR4. The fifth pixel transistor of the plurality offirst pixel transistors may be disposed to overlap, for example, aportion of the first pixel region LR1 and a portion of the second pixelregion LR2. In some embodiments, the fifth pixel transistor may bedisposed to overlap, for example, a portion of the second pixel regionLR2 and a portion of the third pixel region LR3. If the fifth pixeltransistor is disposed to overlap a portion of the first pixel regionLR1 and a portion of the second pixel region LR2, the fifth pixeltransistor may be TR311. In this case, the fourth pixel transistor maybe TR313. If the fifth pixel transistor is disposed to overlap a portionof the second pixel region LR2 and a portion of the third pixel regionLR3, the fifth pixel transistor may be TR314. In this case, the fourthpixel transistor may be TR313. One of the second and third pixeltransistors may be TR312.

For example, if the plurality of first pixel transistors are drivingtransistors SF1 and SF2 as shown in FIG. 27 , the fourth pixeltransistor SF1 may be TR313, and the fifth pixel transistor SF2 may beTR311. For example, if the plurality of first pixel transistors areselection transistors SEL1 and SEL2 as shown in FIG. 28 , the fourthpixel transistor SEL1 may be TR313, and the fifth pixel transistor SEL2may be TR311. For example, if the plurality of first pixel transistorsare reset transistors RG1 and RG2 as shown in FIG. 29 , the fourth pixeltransistor RG1 may be TR313, and the fifth pixel transistor RG2 may beTR314.

Hereinafter, an image sensor according to some embodiments of thepresent inventive concept will be described with reference to FIGS. 2 to6, 10, 26 and 32 to 37 . For brevity and clarity of explanation,repeated descriptions may be omitted. FIGS. 32, 36 and 37 are viewsshowing one unit pixel by enlarging a part of the sensor array region Iof FIG. 2 .

Referring to FIGS. 2, 3, 10, 26 and 32 , the first to fourth regions R1to R4 included in the unit pixel including the first to eight regions R1to R8 of the image sensor according to some embodiments of the presentinventive concept may be substantially the same as those described withreference to FIG. 26 .

In some embodiments, the fifth, sixth, seventh, eight regions R5, R6, R7and R8 may be arranged in the substrate 100 as illustrated in FIG. 32 .The fifth region R5 may be disposed adjacent to the fourth region R4 inthe first direction D1. The sixth region R6 may be disposed adjacent tothe fifth region R5 in the first direction D1. The seventh region R7 maybe disposed adjacent to the sixth region R6 in the first direction D1.The eighth region R8 may be disposed adjacent to the seventh region R7in the first direction D1. The components included in the fifth toeighth regions R5 to R8 may be substantially the same as those describedwith reference to FIG. 10 .

The pixel transistors SF, SEL and RG in FIGS. 33 to 35 may besubstantially the same as the pixel transistors SF, SEL and RG describedwith reference to FIGS. 4 to 6 . Referring to FIGS. 32 and 33 , theimage sensor according to some embodiments of the present inventiveconcept may include first to third pixel transistors SF, RG and SEL.

In some embodiments, the unit pixel including the first to eighthregions R1 to R8 may include driving transistors SF1 and SF2 as theplurality of first pixel transistors as illustrated in FIG. 33 .

Referring to FIGS. 32 and 34 , in some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include selectiontransistors SEL1 and SEL2 as the plurality of first pixel transistors.

Referring to FIGS. 32 and 35 , in some embodiments, the unit pixelincluding the first to eighth regions R1 to R8 may include resettransistors RG1 and RG2 as the plurality of first pixel transistors.

In some embodiments, the plurality of first pixel transistors mayinclude a fourth pixel transistor and a fifth pixel transistor.

Referring to FIGS. 32 to 36 , the fourth pixel transistor may bedisposed to overlap, for example, a portion of the first pixel regionLR1 and a portion of the second pixel region LR2. The fifth pixeltransistor may be disposed to overlap, for example, a portion of thethird pixel region LR3 and a portion of the fourth pixel region LR4. Forexample, the fourth pixel transistor may be TR361. The fifth pixeltransistor may be, for example, TR362. For example, if the plurality offirst pixel transistors are driving transistors SF1 and SF2 as shown inFIG. 33 , the fourth pixel transistor SF1 may be TR361, and the fifthpixel transistor SF2 may be TR362. Each of the second and third pixeltransistors may be one of the TR363 and TR364.

Referring to FIGS. 32 to 35 and 37 , the fourth pixel transistor may bedisposed in either the third pixel region LR3 or the fifth pixel regionLR5. The fifth pixel transistor may be disposed in either the sixthpixel region LR6. For example, the fourth pixel transistor may be eitherTR371 or TR373. The fifth pixel transistor may be TR374. One of thesecond and third pixel transistors may be TR372.

For example, if the plurality of first pixel transistors are selectiontransistors as shown in FIG. 34 , the fourth pixel transistor SEL1 maybe TR371 and the fifth pixel transistor SEL2 may be TR374. For example,if the plurality of first pixel transistors are reset transistors asshown in FIG. 35 , the fourth pixel transistor RG1 may be TR373 and thefifth pixel transistor RG2 may be TR374.

Although the arrangement of the first to third pixel transistors SF, RGand SEL has been described with reference to the accompanying drawings,those are examples, and the present inventive concept is not limitedthereto. It will be understood that if the first to third pixeltransistors SF, RG and SEL are disposed in a plurality of pixel regionsLR1 to LR4 included in the unit pixel, various arrangements may bepossible.

Although a case where the plurality of first pixel transistors includetwo or three pixel transistors has been described with reference to theaccompanying drawings, the present inventive concept is not limitedthereto. For example, it will be understood that the first pixeltransistors may include more than four pixel transistors. In addition,in FIGS. 3, 7 to 10, 14 to 18B, 22 to 26, 30 to 32, 36 and 37 , theshape of each components is provided for illustration of layout only andmay not show shapes of actual components. Accordingly, it will beunderstood that the present inventive concept is not limited to theshape and the arrangement of the components shown in the drawings.

As used herein the term “and/or” includes any and all combinations ofone or more of the associated listed items.

While the present inventive concept has been shown and described withreference to example embodiments thereof, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope of thepresent inventive concept as defined by the following claims. It istherefore desired that the present embodiments be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims rather than the foregoing description to indicatethe scope of the invention.

1. An image sensor comprising: a floating diffusion region; first andsecond photoelectric conversion elements connected to the floatingdiffusion region; first and second driving transistors connected to thefloating diffusion region and connected to each other in parallel; firstand second selection transistors connected to the first and seconddriving transistors and connected to each other in parallel; and firstand second reset transistors connected to the floating diffusion regionand connected to each other in series.
 2. The image sensor of claim 1,wherein the first selection transistor and the second selectiontransistor are disposed symmetrically.
 3. The image sensor of claim 2,wherein the floating diffusion region, the first and secondphotoelectric conversion elements are included in a pixel group, andwherein the first selection transistor and the second selectiontransistor are disposed near corners of the pixel group.
 4. The imagesensor of claim 1, further comprising first and second transfer gatescorresponding to the first and second photoelectric conversion elements,wherein the first and second transfer gates are arranged in a firstdirection, and wherein the first reset transistor and the first transfergate are arranged in a second direction perpendicular to the firstdirection.
 5. The image sensor of claim 4, wherein the first resettransistor, the first driving transistor and the first selectiontransistor are arranged in the first direction.
 6. The image sensor ofclaim 1, further comprising a third driving transistor connected to thefloating diffusion region, wherein the first driving transistor, thesecond driving transistor and the third driving transistor are connectedin parallel.
 7. An image sensor comprising: a floating diffusion region;first and second photoelectric conversion elements connected to thefloating diffusion region; first and second driving transistorsconnected to the floating diffusion region and connected to each otherin parallel; and first and second selection transistors connected to thefirst and second driving transistors and connected to each other inparallel.
 8. The image sensor of claim 7, wherein the first selectiontransistor and the second selection transistor are disposedsymmetrically.
 9. The image sensor of claim 8, wherein the floatingdiffusion region, the first and second photoelectric conversion elementsare included in a pixel group, and wherein the first selectiontransistor and the second selection transistor are disposed near cornersof the pixel group.
 10. The image sensor of claim 7, further comprisinga reset transistor connected to the floating diffusion region.
 11. Theimage sensor of claim 10, wherein the reset transistor comprises firstand second reset transistors connected to each other in series.
 12. Theimage sensor of claim 10, further comprising first and second transfergates corresponding to the first and second photoelectric conversionelements, wherein the first and second transfer gates are arranged in afirst direction, and wherein the reset transistor, the first drivingtransistor and the first selection transistor are arranged in the firstdirection.
 13. The image sensor of claim 12, wherein the resettransistor and the first transfer gate are arranged in a seconddirection perpendicular to the first direction.
 14. The image sensor ofclaim 7, further comprising a third driving transistor connected to thefloating diffusion region, wherein the first driving transistor, thesecond driving transistor and the third driving transistor are connectedin parallel.
 15. An image sensor comprising: a floating diffusionregion; first and second photoelectric conversion elements connected tothe floating diffusion region; first and second driving transistorsconnected to the floating diffusion region and connected to each otherin parallel; and first and second reset transistors connected to thefloating diffusion region and connected to each other in series.
 16. Theimage sensor of claim 15, further comprising first and second selectiontransistors connected to the first and second driving transistors,wherein the first and second selection transistors are connected to eachother in parallel.
 17. The image sensor of claim 16, the first drivingtransistor, the second driving transistor, the first reset transistorand the second reset transistor are disposed between the first andsecond selection transistors.
 18. The image sensor of claim 15, furthercomprising first and second transfer gates corresponding to the firstand second photoelectric conversion elements, wherein the first andsecond transfer gates are arranged in a first direction, and wherein thefirst reset transistor and the first transfer gate are arranged in asecond direction perpendicular to the first direction.
 19. The imagesensor of claim 18, wherein the first reset transistor and the firstdriving transistor are arranged in the first direction.
 20. The imagesensor of claim 15, further comprising a third driving transistorconnected to the floating diffusion region, wherein the first drivingtransistor, the second driving transistor and the third drivingtransistor are connected in parallel.